how to use %XTIME: notification from modem

I'm using 

AT_MONITOR(catch_all, ANY, on_modem_at_notification);
and I'm just printing the notification on reception:
static void on_modem_at_notification(const char *notif)
{
printk("at notif: %s", notif);
}
one that I am receiving is:
at notif: %XTIME: "80","42601121904280","01"
I would love to use that one to get the Timezone out of it.
But I'm a bit puzzled by the format of the timezone (I guess it should return  +08 here in Belgium, which is +2h)
From the reference in your spec (3GPP TS 24.008 Ch. 10.5.3.8 Time Zone) I could not really depict the format of this "80". Could you give more details?
I am also not fully understanding how the daylight saving is working. How will the whole string change in the winter. Will the last "01" change to "00" then? And what will happen with the "80"
I do understand I need to have a backup solution, because I will not always receive this %XTIME: since operators are not always providing the Timezone and daylight saving properties.
I am using the date_time functionality as provided by nordic on nRF9160 and I suppose I get this %XTIME because of that. But it is also possible I will not get it, right?
Lot of questions, so small overview:
Q1) about the format of this "80" which is "08" in your reference
Q2) what to expect in winter with respect to daylight saving
Q3) why am I receiving %XTIME and is it correct that I might not receive it, and that I receive it because I use date_time
Related